Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like, conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer. The absorbent core can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the trade name HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body fluid.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators may include alarm devices that are designed to assist parents or attendants in identifying a wet diaper condition early on. These devices produce either a visual or an audible signal. Many of these devices rely on electronics, which may increase the expense of the absorbent article. Further, electronic devices rely on electrical sources and may be prone to failure if not utilized for an extended period of time.
Problems, however, have been encountered in designing a signaling device that does not appreciably increase the cost of the absorbent article, while providing a meaningful signal to the caregiver without relying on an electrical source for operation.